The two focal areas of the patent are the "L" shaped fixed jaw (marked 17 in the drawing) and the interface between the adjustment screw and connecting link. The "L" shaped jaw piece is to resist stress cracking and failure. The enlarged end on the link is to retain it in the frame. The patent is presented as an improvement to no. 1,489,458.

Compare these features to comparable parts of the W.E. Pugh et. al. February 7, 1950 patents (nos. 2,496,308 and 2,496,309).